On the Grassmann space representing the lines of an affine space

In 1982, Bichara and Mazzocca characterized the Grassmann space Gr(1,A) of the lines of an affine space A of dimension at least 3 over a skew-field K by means of the intersection properties of the three disjoint families @S"1,@S"2 and T of maximal singular subspaces of Gr(1,A). In this paper, we deal with the characterization of Gr(1,A) using only the family @[email protected]"[email protected][email protected]"2 of maximal singular subspaces.